Evaluating Alternative Operations Strategies to Improve Travel Time ...

SHRP 2 L11: Final Report
Current projections indicate that hybrid, electric, and high-mileage gasoline and diesel vehicles
will become an increasing share of the nation’s vehicle fleet, thereby reducing the amount of gas
tax revenue that is generated. Over the next 20 years, it is likely that the nation will become
increasingly dependent on road pricing for generating transportation revenue. The advantage of
road pricing is that it is a fee directly related to the use of the facility. Different rates can be
charged based on the vehicle damage (weight), the number of occupants, the type of facility used,
and the number of miles traveled. Access to transportation facilities can be priced so that the
system operates like a utility with demand spread to times or roads that are less congested. VMT
metering and charging systems could, from a technical perspective, be implemented quite rapidly.
In contrast to a general system of VMT fees for all vehicles, weight-distance truck tolls could be
planned and implemented now.
The issue of mobility equity associated with congestion pricing can also be addressed through
properly aligned incentives. This revenue stream can be directed to provide toll discounts to
selected travel groups and/or reduced cost transit options in the corridor. Reserving some amount
of the revenue stream to support enhanced transit services or to reward agencies or private
companies providing reliable and speedy service could also be considered. At the same time, care
is necessary to ensure that those priced off congested highways indeed have viable transit options.
Public support comes from a conviction that there is some benefit for everyone. Accordingly, some
portion of revenue from road pricing may be used to enhance other modes of travel, such as transit,
and transit service may be integrated into the project design so that transit passengers benefit
directly.
Travelers and shippers behave to maximize the value of their travel experience. Their behaviors
can be influenced by prices and service quality. Pricing alone will give people incentives to modify
travel behaviors and reduce their use of congested facilities if the prices exceed the value of the
trip at a particular time and place. For some, of course, even high prices will not discourage travel.
Such behaviors will be dependent on traveler/shipper characteristics, such as income, commodity
type, and situational factors (such as the importance of a particular trip at a particular time). The
implications of pricing, including the effects on behaviors and the equity consequences, are
complex and difficult to anticipate. However, the developing body of evidence suggests that:
• pricing is an effective strategy for managing demand
• the equity consequences can in some cases be remediated by the targeted
deployment of funds collected (including discounts or subsidies) providing better
transit services or other benefits that may or may not relate to transportation
• the data collected by location-based pricing schemes is of high value for providing
traffic performance information to users and managers.
Pricing systems can produce the benefit of allowing improved traffic management (including
better travel time reliability) through demand management in time and space as well as improved
performance data and traveler information using location data from tracked (probe) vehicles. The
value and effect of traveler information and pricing is shown in Figure 7.3 below.
One should bear in mind that pricing is not the only means of allocating scare roadway capacity to
users. It has long been recognized that travel time is an implicit or “shadow” price road users pay
to drive on congested roads not subject to tolling or pricing. Thus, historically travel time has been
the primary means of allocating scarce road capacity to vehicles, both spatially and over time. One
of the consequences of making travel time reliability more visible as a cost and an operational
A CONCEPT OF OPERATIONS Page 117